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Angular gyrus

The angular gyrus is a prominent convolution in the human brain, located at the posterior part of the inferior parietal lobule, bordering the temporal and occipital lobes. This region plays a critical role in complex language functions, number processing, spatial cognition, memory retrieval, attention, and aspects of social cognition. Its anatomical and imaging features are essential for both clinical diagnosis and research in neuroanatomy and cognitive neuroscience.

Synonyms:

  • Brodmann area 39

  • Gyrus angularis

  • Angular convolution

Arterial Supply:

  • Primarily supplied by the angular branch of the middle cerebral artery (MCA).

  • Additional minor contributions may come from terminal branches of the posterior cerebral artery (PCA).

Venous Drainage:

  • Drained mainly by the superior sagittal sinus via the superior cerebral veins.

  • Also drained by superficial middle cerebral vein and sometimes by the transverse sinus.

Function:

  • Language processing: Involved in reading, writing, and interpretation of written and spoken language.

  • Mathematical cognition: Supports arithmetic and number processing.

  • Spatial cognition: Helps in spatial orientation and perception.

  • Memory retrieval: Important in recollection of episodic and semantic memory.

  • Social cognition: Plays a role in empathy, theory of mind, and processing metaphors.

  • Attention and integration: Integrates sensory information and helps in attention modulation.

MRI Appearance:

  • T1-weighted imaging:

    • Gray matter of the angular gyrus appears isointense to other cortical regions.

    • Lesions or pathologies (e.g., infarct, tumor) may show as hypointense or hyperintense, depending on the process.

  • T2-weighted imaging:

    • Normal cortex shows as intermediate to high signal compared to white matter.

    • Edema or infarcts appear hyperintense.

  • FLAIR (Fluid-Attenuated Inversion Recovery):

    • Enhances visibility of cortical/subcortical abnormalities.

    • Acute or chronic infarcts, demyelination, or gliosis may appear as hyperintense lesions in the angular gyrus region.

CT Appearance:

  • Normal angular gyrus:

    • Isodense with other cortical gray matter.

    • Bony landmarks: Located above the superior temporal sulcus, posterior to the supramarginal gyrus.

  • Pathological changes:

    • Acute infarct: Hypodense area in the angular gyrus territory.

    • Hemorrhage: Hyperdense if acute blood is present.

    • Chronic infarcts or gliosis: Hypodense, with loss of normal gyral anatomy.

MRI images

Angular gyrus mri 3t image

MRI images

Angular gyrus mri 3t sagittal image

CT image

Angular gyrus CT axial anatomy image -img-00001-00001